KETTERING, Ohio (AP) — Superstorm Sandy's mayhem is upending the final week of the presidential race, with President Barack Obama calling off another of the waning days left to campaign and Republican Mitt Romney struggling to strike the right tone.

The White House announced Tuesday that Obama will not go ahead with a Wednesday campaign swing through Ohio so he can remain at the White House to monitor recovery efforts for the storm that practically shut down New York City and spread damage across the East Coast.

Romney and running mate Paul Ryan initially announced they were canceling events out of sensitivity for the millions of Americans in Sandy's path. But with only a week left to try to toss Obama from office, the GOP campaign was back on Tuesday with events in the critical Midwestern swing states of Ohio and Iowa, albeit with changes to the program.

Romney was holding a "storm relief event" in Kettering, Ohio, at the same arena as his previously scheduled political rally and with the same celebrity line-up — NASCAR driver Richard Petty and country music singer Randy Owen. The event was moved up by four hours and aides said the tone would be changed, with no attacks on the president back at the White House overseeing the response.

Effusive praise for Obama's leadership came in Tuesday from a surprising source — New Jersey Gov. Chris Christie, a Republican who has been campaigning for Romney across the country and a pointed Obama critic. He said in a series of morning television show interviews that Obama was in touch throughout the night as the storm struck New Jersey, including a call at midnight, and effectively expedited much-needed disaster relief.

"The president has been all over this and he deserves great credit," Christie told MSNBC's "Morning Joe." ''I've been on the phone with him, like I said, yesterday personally three times. He gave me his number at the White House, told me to call him if I need anything, and he absolutely means it. It's been very good working with the president."

The White House said Obama was speaking frequently to other governors and mayors in affected areas. The White House released a photo of the president receiving a videoconference update on the response from the Situation Room.

Millions were left without power as the deadly storm whipped its way through presidential battlegrounds like North Carolina, Virginia and New Hampshire and sprawled as far as the Great Lakes, where gales threatened Ohio's and Wisconsin's lakeside regions.

David Letterman, continuing his "Late Show" in storm-damaged New York without an audience, joked: "The storm has stopped the presidential campaign, so at least some good has come of it."

Some election centers in the affected states were shut down, but early voting continued in areas outside Sandy's path. After casting her ballot for Obama at the Franklin County early voting center Tuesday, Lydia Strauss, of Columbus, said she didn't anticipate the storm changing the outcome in Ohio.

"People feel strongly about this election and they're not going to be deterred," said the 42-year-old social worker.

Romney planned to hold three campaign events in Florida on Wednesday with former Gov. Jeb Bush and Sen. Marco Rubio. Ryan was returning to his regular schedule Wednesday, campaigning across his home state of Wisconsin before going trick or treating with his children.

Romney's campaign grappled with how he should respond to the storm, without the official duties that gave Obama a leadership role. When the president rushed out of battleground Florida on Monday morning before a scheduled rally to return to the White House to monitor the storm, Romney aides initially said he and Ryan would continue working for votes away from the storm's path. Then communications director Gail Gitcho announced a change in plans just as Romney was appearing at a rally in Ohio.

"Out of sensitivity for the millions of Americans in the path of Hurricane Sandy, we are canceling tonight's events with Gov. Romney in Wisconsin and Congressman Ryan in Melbourne and Lakeland, Florida," she wrote in an email to reporters. "We are also canceling all events currently scheduled for both Gov. Romney and Congressman Ryan on Tuesday."

But they apparently concluded that Romney couldn't afford to waste time out of the spotlight in such a closely fought race, with polling showing an Obama advantage in several swing states. Later Monday evening, the campaign announced the Kettering event, with local news reports saying supporters should bring food donations.

The event had all the trappings of a typical Romney campaign rally. A biographical video first aired at the Republican National Convention this summer was showing on large screens set up for several hundred supporters gathered inside a school basketball arena before Romney took the stage.

Outside, signs noted that the arena track would be closed to the public on Tuesday "for the Republican campaign rally." Credentials distributed to reporters described the event as a "victory rally."

Inside, campaign staff and volunteers collected donations in the back of the room. They stacked canned goods, boxes of diapers, chocolate bars, bottled water, fleece blankets and jars of peanuts.

Asked why she was there, 51-year-old Republican Jackie Seals, a school custodian from Kettering, said: "I'm here to support Mitt Romney." A button proclaiming, "No ObamaCare!" was pinned to her sweater. She had two cans of soup in her purse to donate, but said she wasn't sure who to give them to.

The Romney camp also announced that a political rally in Des Moines, Iowa, would go on at the same time as previously scheduled Tuesday night, with Ann Romney filling in for her husband as the headliner. Ryan was slated to visit campaign offices in his home state of Wisconsin to thank the volunteers helping to collect relief supplies for storm victims.

Romney campaign spokesman Kevin Madden said the campaign was in contact with local relief organizations and the Red Cross to make sure the supplies they were collecting Tuesday would be useful.

"We checked to make sure the supplies would be helpful and welcomed as part of our volunteer effort. And our own volunteers will be personally delivering the supplies to the relief center," Madden said.